There's a few reasons for this.
The first is I screwed up the formatting for the Kindle and Smashwords versions and now I have to redo it. Formatting sucks too and I haven't done it in a while, so it's probably going to take me longer than it should.
Second reason is my day job and daily life. Of course, the week I want to rerelease Snapshots, everything has to happen. My hours go up, I have to go to my parents' house (an hour and half drive ONE way.) I'm in a time crunch, and while I'm sure I could get everything done by the 23rd, I'm not that sure.
The last reason is everyone else. This week alone I have gotten a bunch of emails about book releases, free days, and cover reveals I signed up for, you guessed it, on the 23rd. There's just so much going on and I agreed to it all before I had a date for Snapshots. And I know the week after there will be plenty of the same, but I won't be taking part in any of it and the people who are going to help me won't be either (at least some of them, I hope.) I feel bad not giving their books the spotlight as well as taking the spotlight away from Snapshots.
The new date will be JULY 28th, so not a whole lot later, but enough that I should get everything done in time. With my sanity intact. Win! I will be emailing all the participants of the relaunch with this info too. Hopefully, no one will have to drop out because of the change.